I have my hard drives set to shut off after 2 hours in Power Options in Windows XP sp1. Many times when i come to use my computer after being away from it for 8-10 hours, I'll notice the hard drive light flicking as though there were major harddrive use going on, but no programs running, and i haven't touched the computer yet...so the harddrive should be shut down.
Any thoughts on why this is?

thanks for the reply!
i ran adaware, spybot, and registry mechanic and restarted, so i'll keep an eye out to see if that helps.
I didn't see anything about APM (automatic power management?) in the BIOS settings, but i saw that the option to shutdown harddrives was disabled. The only options to enable it was 1-minute increments up to 15 minutes. I don't want my drives to shut down after only 15 minutes though... do i have to enable for my drives to shut down?